Hip joint device and method

ABSTRACT

A medical device for implantation in a hip joint of a patient, the natural hip joint having a ball shaped caput femur integrated with a collum femur having a collum and caput center axis, extending longitudinal along the collum and caput femur, in the center thereof, as the proximal part of the femoral bone with a convex hip joint surface towards the centre of the hip joint and a bowl shaped acetabulum as part of the pelvic bone with a concave hip joint surface towards the centre of the hip joint, the medical device comprising; an artificial caput femur comprising a convex surface towards the centre of the hip joint, an elongated portion adapted to be connected to a prosthetic spherical portion of said artificial convex caput femur and fixated to the pelvic bone of the human patient.

FIELD OF INVENTION

The present invention relates generally to a medical device forimplantation in a hip joint, and a method of providing said medicaldevice.

BACKGROUND

The hip joint is a synovial joint, joining the pelvis to the proximalportion of the femoral bone. Synovial joints are the most common typesof joints in mammals, and are typical of nearly all limb joints. Thecontacting surfaces of said the pelvic, the acetabulum, and thecontacting surface of the femoral bone, the caput femur, are smooth androunded, and covered by articular cartilage. A synovial membrane,encapsulates the joint, forming a hip joint cavity, which containssynovial fluid. Outside the synovial membrane is a fibrous capsule andligaments, forming an articular capsule.

There are both natural and pathological processes leading todeteriorated joint function. With age and wear, the articular cartilagebecomes less effective as a shock absorber and a lubricated surface.Different degenerative joint diseases, such as arthritis,osteoartrithis, or osteoarthrosis, accelerate the deterioration.

Hip joint Osteoarthritis is a syndrome in which low-grade inflammationresults in pain in the hip joints, caused by abnormal wearing of theCartilage that acts as a cushion inside if the hip joint. This abnormalwearing of the cartilage also results in a decrease of the jointslubricating fluid called Synovial fluid. Hip joint Osteoarthritis isestimated to affect 80% of all people over 65 years of age, in more orless serious forms.

The present treatment for hip osteoarthritis comprises NSAID drugs,local injections of Hyaluronic acid or Glucocorticoid to helplubricating the hip joint, and replacing parts of the hip joint with aprosthesis through hip joint surgery.

The replacing of parts of the hip joint is one of the most commonsurgeries to date performed at hundreds of thousands of patients in theworld every year. The most common method comprises placing a metalprosthesis in Femur and a plastic bowl in Acetabulum. This operation isusually done through a lateral incision in the hip and upper thigh andthrough, Fascia Lata and the lateral muscles of the thigh. To get accessto the hip joint, the supporting hip joint capsule attached to Femur andIlium of Pelvis needs to be penetrated, making it difficult to get afully functional joint after the surgery. Femur is then cut at the neckwith a bone saw and the prosthesis is placed in femur either with bonecement or without. Acetabulum is slightly enlarged using an Acetabularreamer, and the plastic bowl is positioned using screws or bone cement.The complications after hip joint surgery includes dislocation of thehip joint and loosening of the prosthesis from its fixation in thefemoral bone. The loosening and/or dislocation of the prosthesis couldbe induced by an abnormal strain being placed on the hip joint from e.g.the patient falling or making a rapid movement of the hip, or by abodily macrophage reaction.

The surgery typically requires one week of hospitalization due to theincreased risk of infection. The recovery process is on average about 6weeks, but even after this period the patient should not perform anyphysical activates that places large strain on the joint.

SUMMARY

According to one embodiment of a medical device for implantation in ahip joint of a patient, the natural hip joint having a ball shaped caputfemur integrated with a collum femur having a collum and caput centeraxis, extending longitudinal along the collum and caput femur, in thecenter thereof, as the proximal part of the femoral bone with a convexhip joint surface towards the centre of the hip joint and a bowl shapedacetabulum as part of the pelvic bone with a concave hip joint surfacetowards the centre of the hip joint, the medical device comprising; anartificial caput femur comprising a convex surface towards the centre ofthe hip joint, an elongated portion adapted to be connected to aprosthetic spherical portion of said artificial convex caput femur andfixated to the pelvic bone of the human patient, said artificial convexcaput femur is adapted to, when implanted, be fixated to the pelvic boneof the human patient through said elongated portion fixation to thepelvic bone, and be in movable connection with a prosthetic artificialacetabulum surface fixated to the femoral bone of the patient,comprising at least one extending portion adapted to clasp saidprosthetic spherical portion, wherein said elongated portion comprises arestricting portion adapted to restrict the motion range of theartificial acetabulum in relation to said artificial convex caput femur,and wherein said restricting portion of said elongated portion isadapted to enable an advantageous motion range in relation to saidartificial acetabulum.

According to one embodiment, said elongated portion comprises at leastone recess adapted to receive a portion of said prosthetic artificialacetabulum, when implanted.

According to one embodiment, said recess is adapted to be placed frontalto the coronal pelvis plane, when implanted.

According to one embodiment, said recess is adapted to be placed in thefrontal quadrant, when implanted.

According to one embodiment, said recess is adapted to be placed in thedorsal quadrant, when implanted.

According to one embodiment, said recess is adapted to be placed in theproximal quadrant, when implanted.

According to one embodiment, said recess is adapted to be placed in thedistal quadrant, when implanted.

According to one embodiment, said recesses is more than 2 mm deep.

According to one embodiment, said recesses is more than 4 mm deep.

According to one embodiment, said recesses is more than 6 mm deep.

According to one embodiment, said recesses is more than 8 mm deep.

According to one embodiment, said elongated portion comprises anadaptation adapted to receive said extending portion when implanted.

According to one embodiment, said adaptation comprises a bent portion ofsaid elongated portion.

According to one embodiment, said bent portion is bent such that saidrestricting portion of said elongated portion mainly is placed frontalto the coronal pelvis plane, when implanted and being in the baseposition.

According to one embodiment, said bent portion is bent such that saidrestricting portion of said elongated portion mainly is placed dorsal tothe coronal pelvis plane, when implanted and being in the base position.

According to one embodiment, said bent portion is bent such that saidrestricting portion of said elongated portion mainly is placed in thefrontal quadrant, when implanted and being in the base position.

According to one embodiment, said bent portion is bent such that saidrestricting portion of said elongated portion mainly is placed in thedorsal quadrant, when implanted and being in the base position.

According to one embodiment, said bent portion is bent such that saidrestricting portion of said elongated portion mainly is placed in theproximal quadrant, when implanted and being in the base position.

According to one embodiment, said bent portion is bent such that saidrestricting portion of said elongated portion mainly is placed in thedistal quadrant, when implanted and being in the base position.

According to one embodiment, a cross-section of said restricting portionof said elongated portion, perpendicular to the caput and collum centeraxis, comprises a first distance and a second distance, wherein a centerpoint of a line of said first distance intersects a center point of aline of said second distance, and wherein said first distance is shorterthan said second distance. According to one embodiment, said firstdistance is a cross-sectional distance of a narrow portion if saidelongated portion, and wherein said second distance is a cross-sectionaldistance of a wide portion of said elongated member. According to oneembodiment, said restricting portion of said elongated portion isadapted to be substantially aligned with said collum center axis andadapted to be eccentrically placed in relation to said collum axis, whenimplanted. According to one embodiment, a major portion of saidrestricting portion of said elongated portion is adapted to be placedfrontal to the coronal pelvis plane when implanted.

According to one embodiment, the restricting portion of the elongatedportion is adapted to be placed in the frontal quadrant, when implanted.

According to one embodiment, the restricting portion of the elongatedportion is adapted to be placed in the dorsal quadrant, when implanted.

According to one embodiment, the restricting portion of the elongatedportion is adapted to be placed in the proximal quadrant, whenimplanted.

According to one embodiment, the restricting portion of the elongatedportion is adapted to be placed in the distal quadrant, when implanted.

According to one embodiment, a cross section of the restricting portionof the elongated portion, perpendicular to the collum center axis, iscircular.

According to one embodiment, a cross section of the restricting portionof the elongated portion, perpendicular to the collum center axis, ispolygonal.

According to one embodiment, a cross section of the restricting portionof the elongated portion, perpendicular to the collum center axis, iselliptical.

According to one embodiment, said restricting portion, when implanted,is adapted to be placed such that adduction is restricted more degreesthan flexion.

According to one embodiment, said restricting portion, when implanted,is adapted to be placed such that abduction is restricted more degreesthan flexion.

According to one embodiment, said restricting portion, when implanted,is adapted to be placed such that adduction is restricted more degreesthan extension.

According to one embodiment, said restricting portion, when implanted,is adapted to be placed such that abduction is restricted more degreesthan extension.

According to one embodiment, a medical device system comprises a medicaldevice according to any one of claims 1-34 and a prosthetic replacementfor the acetabulum comprises at least one extending portion adapted toclasp said spherical portion.

According to one embodiment, said prosthetic replacement for theacetabulum comprises an inner and an outer surface, wherein a contactingportion, of said inner surface is spherical and adapted to face thecenter of the hip joint when said medical device is implanted, andwherein said prosthetic replacement for the acetabulum is adapted toreceive said spherical portion, wherein said prosthetic replacement forthe acetabulum comprises at least one extending portion, extending saidcontacting portion of said inner surface such that said at least oneextending portion clasps said spherical portion, such that saidspherical portion is restrained in said medical device, and wherein saidprosthetic replacement for the acetabulum is adapted to be fixated tothe femoral bone of the patient.

According to one embodiment, said prosthetic replacement for theacetabulum is adapted to receive said spherical portion being inconnection with said medical device, wherein:

said inner surface comprises an equator line, being the largest circularcircumference of said inner contacting surface, being a surface adaptedto be in contact with said spherical portion, and

said at least one extending portion passes beyond said equator line,such that the end portion of said contacting portion of said innersurface forms a circular extension line having a smaller circumferencethan said equator line, and

said at least one extending portion circumferentially extendsdiscontinuously along said equator line, such that a portion of saidmedical device can be placed between said extension line and saidequator line.

According to one embodiment, said extension line is placed proximal tothe equator line, when the medical device is implanted.

According to one embodiment, said at least one extending portion extendscircumferentially along said equator line, dorsal to the right-left axisof pelvis when being in the base position.

According to one embodiment, said at least one extending portion extendscircumferentially along said equator line, dorsal to the coronal pelvisplane PXY and proximal to the horizontal pelvis PXZ plane when being inthe base position.

According to one embodiment, said at least one extending portion extendscircumferentially along said equator line, dorsal to the coronal pelvisplane PXY and distal to the horizontal pelvis PXZ plane when being inthe base position.

According to one embodiment, at least one first extending portionextends circumferentially along said equator line dorsal to the coronalpelvis plane PXY and proximal to the horizontal pelvis PXZ plane, and atleast one second extending portion extends dorsal to the coronal pelvisplane PXY and distal to the horizontal pelvis PXZ plane when being inthe base position.

According to one embodiment, said at least one extending portion extendscircumferentially along said equator line, in the proximal quadrant ofthe equator line when being in the base position.

According to one embodiment, said at least one extending portion extendscircumferentially along said equator line, in the distal quadrant of theequator line when being in the base position.

According to one embodiment, two extending portions extendscircumferentially along said equator line, in the distal and proximalquadrant thereof when being in the base position.

According to one embodiment, said at least one extending portion extendscircumferentially along said equator line, in the proximal and dorsalquadrant thereof when being in the base position.

According to one embodiment, said at least one extending portion extendscircumferentially along said equator line, in the distal and dorsalquadrant thereof when being in the base position.

According to one embodiment, at least one extending portion extendscircumferentially along said equator line, in the distal, dorsal andproximal quadrant thereof when being in the base position.

According to one embodiment, at least a first portion of said prostheticreplacement for the acetabulum is an extending portion, extending beyondsaid circular equator line, and at least a second portion is a portionnot extending beyond said circular equator line, wherein said secondportion circumferentially extends along at least ¼ of said circularequator line.

According to one embodiment, at least a first portion of said prostheticreplacement for the acetabulum is an extending portion, extending beyondsaid circular equator line, and at least a second portion is a portionnot extending beyond said circular equator line, wherein said secondportion circumferentially extends along at least ⅓ of said circularequator line.

According to one embodiment, at least a first portion of said prostheticreplacement for the acetabulum is an extending portion, extending beyondsaid circular equator line, and at least a second portion is a portionnot extending beyond said circular equator line, wherein said secondportion circumferentially extends along at least ½ of said circularequator line.

According to one embodiment, at least a first portion of said prostheticreplacement for the acetabulum is an extending portion, extending beyondsaid circular equator line, and at least a second portion is a portionnot extending beyond said circular equator line, wherein said firstportion circumferentially extends along at least ¼ of said circularequator line.

According to one embodiment, at least a first portion of said prostheticreplacement for the acetabulum is an extending portion, extending beyondsaid circular equator line, and at least a second portion is a portionnot extending beyond said circular equator line, wherein said firstportion circumferentially extends along at least ⅓ of said circularequator line.

According to one embodiment, at least a first portion of said prostheticreplacement for the acetabulum is an extending portion, extending beyondsaid circular equator line, and at least a second portion is a portionnot extending beyond said circular equator line, wherein said firstportion circumferentially extends along at least ½ of said circularequator line.

According to one embodiment, at least a first portion of said prostheticreplacement for the acetabulum is an extending portion, extending beyondsaid circular equator line, and at least a second portion is a portionnot extending beyond said circular equator line, wherein said firstportion circumferentially extends along at least 1/10 of said circularequator line.

According to one embodiment, at least a first portion of said prostheticreplacement for the acetabulum is an extending portion, extending beyondsaid circular equator line, and at least a second portion is a portionnot extending beyond said circular equator line, wherein said firstportion circumferentially extends along at least 1/10 of said circularequator line, and said second portion circumferentially extends along atleast ¼ of said circular equator line.

According to one embodiment, at least two first portions of saidprosthetic replacement for the acetabulum are extending portions,extending beyond said circular equator line, and at least a secondportion is a portion not extending beyond said circular equator line,wherein said first portions each circumferentially extends along atleast 1/10 of said circular equator line, and said second portioncircumferentially extends along at least A of said circular equatorline.

According to one embodiment, at least two first portions of said medicaldevice are extending portions, extending beyond said circular equatorline, and wherein one of said extending portions extends further thanthe other extending portion.

According to one embodiment, said medical device further comprises twosecond portions not extending beyond said circular equator line, andwherein said two first extending portion circumferentially extends alongsaid equator line between said two second portions.

According to one embodiment, said extending portion adapted to claspsaid spherical portion and said restricting portion of said elongatedportion of said medical device is adapted to, when implanted in saidbase position, be placed such that their placement in relation to eachother creates an advantageous motion range.

According to one embodiment, said extending portion said restrictingportion of said elongated portion is adapted to be placed in relation toeach other when implanted in said base position, such that adduction isrestricted more degrees than flexion.

According to one embodiment, said extending portion said restrictingportion of said elongated portion is adapted to be placed in relation toeach other when implanted in said base position, such that abduction isrestricted more degrees than flexion.

According to one embodiment, said extending portion said restrictingportion of said elongated portion is adapted to be placed in relation toeach other when implanted in said base position, such that adduction isrestricted more degrees than extension.

According to one embodiment, said extending portion said restrictingportion of said elongated portion is adapted to be placed in relation toeach other when implanted in said base position, such that abduction isrestricted more degrees than extension.

The artificial hip joint surface, according to any of the embodimentsabove may comprise an artificial convex caput femur or an artificialconvex caput femur surface or an artificial concave acetabulum or anartificial concave acetabulum surface.

A surgical and/or laparoscopic and/or arthroscopic method of implantingthe medical device is further provided, the method comprising the stepsof: cutting the skin of the patient, dissecting an area of the pelvicbone, fixating the medical device to the pelvic bone such that themedical device is in movable connection with a prosthetic artificialacetabulum surface fixated to the femoral bone of the patient and thatthe restricting portion of the elongated portion is placed such toenable an advantageous motion range in relation to said artificialacetabulum.

The restricting portion of said elongated portion is placed, such thatadduction is restricted more degrees than flexion.

The restricting portion of said elongated portion is placed, such thatabduction is restricted more degrees than flexion.

The restricting portion of said elongated portion is placed, such thatadduction is restricted more degrees than extension.

The restricting portion of said elongated portion is placed, such thatabduction is restricted more degrees than extension.

The restricting portion of said elongated portion is placed in any ofthe ways described in above.

Please note that any embodiment or part of embodiment as well as anymethod or part of method could be combined in any way. All examplesherein should be seen as part of the general description and thereforepossible to combine in any way in general terms.

BRIEF DESCRIPTION OF DRAWINGS

The invention is now described, by way of example, with reference to theaccompanying drawings, in which:

FIG. 1 a shows pelvis in a frontal view,

FIG. 1 b shows pelvis in a frontal view,

FIG. 1 c shows the hip joint in section,

FIG. 2 a shows pelvis in a lateral view,

FIG. 2 b shows pelvis in a lateral view,

FIG. 2 c shows pelvis in a perspective view from below,

FIG. 2 d shows pelvis in a perspective view from below,

FIG. 2 e shows the acetabulum, schematically,

FIG. 2 f shows the acetabulum, schematically,

FIG. 2 g shows pelvis in a perspective view from below,

FIG. 3 a shows the hip joint in section,

FIG. 3 b shows the step of removing a proximal part of the caput femur,

FIG. 4 a shows the reaming of the collum and caput femur,

FIG. 4 b shows the step of applying an adhesive to the createdhemi-spherical cavity in the femoral bone,

FIG. 5 shows the collum and caput femur when a medical device gas beenfixated,

FIG. 6 a shows the femoral bone when a medical device having a concavecontacting surface has been provided to the hemi-spherical cavity,

FIG. 6 b shows the femoral bone when a medical device having a concavecontacting surface has been provided to the hemi-spherical cavity,

FIG. 6 c shows the medical device fixated to the surgically cut caputfemur using screws,

FIG. 6 d shows the medical device fixated to the femoral bone usingfixating portions,

FIG. 6 e shows the medical device in which fixating portions areadditionally fixated using screws,

FIG. 7 a shows the medical device in which the fixating portions extendsbeyond the greatest circumference of the surgically cut caput femur,

FIG. 7 b shows the medical device additionally fixated using a fixatingband,

FIG. 7 c shows three different embodiment of medical devices comprisingfixating portions which are slightly tilted towards the collum and caputfemur,

FIG. 7 d shows two embodiments in which the concave contacting surfaceonly comprises the part placed inside of the concave cavity,

FIG. 7 e shows two embodiments in which the artificial acetabulumsurface extends into a portion placed on the surface of a sectioncreated when the caput femur is surgically cut,

FIG. 7 f describes the medical device fixated using an elongated member,fixating portions, and screws,

FIG. 8 shows the artificial acetabulum surface in further detail,

FIG. 9 shows a section of the medical device according to the embodimentalso described with reference to FIG. 7 a,

FIG. 10 a shows the step of milling the periphery of the cortical boneof the caput femur,

FIG. 10 b shows the milling of the inside of the cortical bone of thecaput femur,

FIG. 11 shows an artificial convex caput femur surface adapted to beplaced in an artificial acetabulum surface,

FIG. 12 shows the artificial convex caput femur surface as disclosedwith reference to FIG. 11 when mounted in an artificial acetabulumsurface,

FIG. 13 shows the artificial convex caput femur surface as disclosedwith reference to FIG. 11 when mounted in an artificial acetabulumsurface,

FIG. 14 shows the injection of an adhesive in the acetabulum in thepelvic bone,

FIG. 15 shows the placing of a medical device in the reamed acetabulumsurface of the pelvic bone,

FIG. 16 a shows the hip joint in section, separated,

FIG. 16 b shows the hip joint in section, with a prosthetic acetabulumsurface placed in the hemi-spherical cavity in the femoral bone,

FIG. 16 c shows the hip joint in section, with a prosthetic acetabulumsurface placed in the hemi-spherical cavity in the femoral bone,

FIG. 16 d shows the hip joint in section, with a prosthetic acetabulumsurface placed in the hemi-spherical cavity in the femoral bone,

FIGS. 17 a-17 d shows embodiments of the medical device, in side views,

FIG. 18 shows the medical device in section, according to oneembodiment,

FIGS. 19 a-19 k shows cross-sections of embodiments of the medicaldevice,

FIGS. 20 a-20 d shows embodiments of the medical device in sectionalside view and in cross-section.

FIG. 21 a shows pelvis in a lateral view,

FIG. 21 b shows the hip joint in section,

FIGS. 22 a-22 c shows cross-sections of the medical device,

FIG. 23 shows a prosthetic replacement for the acetabulum, according toone embodiment,

FIG. 24 shows the hip joint in section, when a prosthetic replacementfor the acetabulum, and a medical device has been implanted,

FIG. 25 a shows the pelvic region in a frontal view,

FIG. 25 b shows the pelvic region in a frontal view,

FIG. 26 shows the pelvic region in a frontal view,

FIG. 27 shows a medical device placed in the femoral bone,

FIG. 28 a shows the femoral bone in a lateral view,

FIG. 28 b shows the femoral bone in a lateral view,

FIG. 29 shows the femoral bone in a lateral view,

FIG. 30 shows the femoral bone in a lateral view,

FIG. 31 shows the femoral bone in a lateral view,

FIG. 32 shows a medical device placed in the femoral bone,

FIGS. 33 a-33 f shows embodiments of prosthetic replacements for theacetabulum,

FIGS. 34 a-34 d shows embodiments of the medical device in combinationwith embodiments of the prosthetic replacement for the acetabulum, in asectional side view and in cross-section.

DETAILED DESCRIPTION

The hip joint is a synovial ball and socket joint which permits a largemotion range for allowing a plurality of different movements of thelower limb. From a neutral position the following movements of the hipjoint are normally possible: Lateral or external rotation, 30° with thehip extended, 50° with the hip flexed, medial or internal rotation 40°,extension or retroversion 20°, flexion or anteversion 140°, abduction50° with hip extended, 80° with hip flexed, adduction 30° with hipextended, 20° with hip flexed.

When replacing the natural hip joint with a prosthetic hip joint, thedepth of the prosthetic acetabulum will affect the motion range, thedeeper the acetabulum bowl is made the more restrictive it is to themotion range. A deeper bowl has the advantage of reducing the risk ofhip joint luxation, the risk of which is a major drawback withprosthetic hips of today.

The anatomy of the hip joint and its surroundings is further disclosedin: Marieb et al., Human Anatomy, 2003, Benjamin Cummings, SanFrancisco, pages 195-202 and in Moore et al., Clinically orientedanatomy, 1999, Lippincott, Williams & Wilkins, Baltimore, pages 501-653,both hereby incorporated by reference.

Centrally in the body should herein be understood as a point ofreference located at the intersection of the Median plane and theCoronal plane and in the center part of the heart along a longitudinalaxis (Caudal-Cranial). Proximal and distal are direction or locationterms used in relation to said point centrally in the body and hence adistal point is a point farther away from the central point in relationa proximal point of the same structure. Any plane disclosed herein is tobe understood as having infinite extension. Other anatomical terms usedherein are further described in Moore et al., Clinically orientedanatomy, 1999, Lippincott, Williams & Wilkins, Baltimore, pages 2-10,which is hereby incorporated by reference.

Functional hip movements are to be understood as movements of the hipthat at least partly correspond to the natural movements of the hip. Onsome occasions the natural movements of the hip joint might be somewhatlimited or altered after hip joint surgery, which makes the functionalhip movements of a hip joint with prosthetic surfaces somewhat differentthan the functional hip movements of a natural hip joint.

Everyday activities is to be understood as activities which are notconnected to any extreme movements, such that some physical sportsrequire. For example, everyday activities comprise: walking, sitting,cycling etc.

The functional position of an implantable medical device or prosthesisis the position in which the hip joint can perform functional hipmovements. The final position is to be understood as a functionalposition in which the medical device needs no further position change tofunction.

Arthroscopy is to be understood as key hole surgery performed in ajoint, since the arthroscopic procedure could be performed in theabdomen of the patient some of the steps of this arthroscopic procedureis more laparoscopic, however for the purpose of this invention the twoterms arthroscopy and laparoscopy is used synonymously and for thepurpose of this invention the main purpose of these methods are is thatthey are minimally invasive.

Elastic deformation is when a material deforms under stress (e.g.external forces), but returns to its original shape when the stress isremoved. A more elastic material is to be understood as a materialhaving a lower modulus of elasticity. The elastic modulus of an objectis defined as the slope of its stress/strain curve in the elasticdeformation region. The elastic modulus is calculated as stress/strain,where stress is the force causing the deformation, divided by the areato which the force is applied; and strain is the ratio of the changecaused by the stress.

Elasticity is to be understood as a materials ability to deform in anelastic way.

Stiffness is to be understood as the resistance of an elastic body todeformation by an applied force.

Biocompatible material is to be understood as being a material with lowlevel of immune response. Biocompatible materials are sometimes alsoreferred to as biomaterials. Analogous is biocompatible metals abiocompatible metal with low immune response such as titanium ortantalum. The biocompatible metal could also be a biocompatible alloycomprising at least one biocompatible metal.

Form fitting is to be understood as an element having a part or sectionwhich is adapted to enable a mechanical connection of said element to atleast one other element using said part or section. Form fittedstructure is a structure of an element which enables form fitting.

In the following a detailed description of embodiments of the presentinvention will be given. In the drawing figures, like reference numeralsdesignate identical or corresponding elements throughout the severalfigures. It will be appreciated that these figures are for illustrationonly and are not in any way restricting the scope of the invention.Thus, any references to direction, such as “up” or “down”, are onlyreferring to the directions shown in the figures. Also, any dimensionsetc. shown in the figures are for illustration purposes.

FIG. 1 a shows the pelvis in a frontal view. Pelvis comprises the rightand left hip bone making up the pelvic bone, in turn comprising theSacrum 1803, Ilium 1802, Pubis 1804 and Ischium 1801. The hip jointhouses the right and left acetabulum 8 a,b placed laterally and distallyin the pelvis. The acetabulum 8 a,b being a spherically shaped cavity inthe hip bones making up one of the parts of the hip joint, theacetabulum 8 a,b being adapted to house the caput femur 5, being theproximal portion of the femoral bone 7 having a spherical contactingsurface adapted to be placed in the acetabulum 8 a,b and thus creatingthe operable hip joint. The pelvis has a right-left axis X extendingsubstantially from the bottom of the left acetabulum 8 a to the bottomof the right acetabulum 8 b, the pelvis further having a caudal-cranialaxis Y extending perpendicular to said right-left axis, centrally andsubstantially along the length of the patient, passing the dorsalportions of the pubic symphysis 1805 and substantially following thespinal cord 1806, intersecting the left-right axis X.

FIG. 1 b shows the pelvis in a frontal view disclosing a second,displaced coordinate system. The second displaced coordinate system hasits origin O′ in the bottom of the acetabulum bowl 8 a. The axis X and Yhave, in a frontal view, been rotated the angle β, creating the axis X′and Y′. The axis X′ being aligned with the caput and collum femur centeraxis CX, when the hip joint is in its base position when the patient isstanding up or lying down. In said base position, the axis X′ goesthrough a point O′ being the origin O′ in the bottom of the acetabulumbowl 8 a, and a center point CP, being a point in the center of a circledefined by the edges of the acetabulum bowl 8 a, and further trough thetop of the caput femur 5 and following inside of the collum femur 6,aligned with the collum femur 6. The axis Y′ is perpendicular to theaxis X′ and goes through the origin O′ in the bottom of the acetabulumbowl 8 a, parallel to a plane defined by the circle defined by the edgesof the acetabulum bowl 8 a.

FIG. 1 c shows the right pelvic bone 9 in section disclosing the second,displaced coordinate system. The origin O′ is in the bottom of theacetabulum bowl 8. The axis X′ is aligned with the caput 5 and collum 6femur center axis CX, when the hip joint is in its base position whenthe patient is standing, up or lying down with extended leg. In saidbase position the axis X′ is goes through a point O′ being the bottom ofthe acetabulum bowl 8, and a center point CP, being a point in thecenter of a circle defined by the edges of the acetabulum bowl 8, andfurther trough the top of the caput femur 5′ and following inside of thecollum femur 6, aligned with the collum femur 6. The axis Y′ isperpendicular to the axis X′, goes through the origin O′ in the bottomof the acetabulum bowl 8, parallel to the plane PC defined by the circledefined by the edges of the acetabulum bowl 8.

FIG. 2 a shows the pelvis in a lateral view, thus displaying theposterior side of Ilium 1802, the anterior side of Ischium 1801, theanterior side of Pubis 1804, and Sacrum 1803 in a lateral view. Thepelvis has furthermore a dorsoventral axis Z being perpendicular to thecaudal-cranial axis Y and the right-left axis X shown in FIG. 1, andintersecting them both creating a common origin O for the three axisX,Y,Z. The dorsoventral axis Z and the caudal-cranial axis Y thus beingoriented such that a horizontal pelvis plane PXZ extends from thedorsoventral axis Z, and a coronal plane PXY extends from thecaudal-cranial axis Y.

FIG. 2 b shows the pelvis in a plane view from the side and slightlyfrom below, in the direction of the axis X′ (further disclosed withreference to FIGS. 1 b and 1 c). The view of FIG. 2 b displaying theaxis Y′ and Z′ with origin O′ in the bottom of the acetabulum bowl 8making up the acetabulum coordinate system. The axis Y′, Z′, in thisplane view, dividing the acetabulum bowl 8 into four quadrants: theproximal-frontal quadrant 1807, the distal-frontal quadrant 1808, thedistal-dorsal quadrant 1809 and the proximal-dorsal quadrant 1810.

FIG. 2 c shows the pelvis in a perspective view from below and slightlyfrom the front, displaying the right-left axis X passing through thecenter of the right and left acetabulum 8. The right-left axis X isperpendicular to the dorsoventral axis Z which also is perpendicular tothe caudal-cranial axis Y. The coronal plane PXY extends from thedorsoventral axis Y, and the horizontal pelvis plane PXZ extends fromthe dorsoventral axis Z, thus being perpendicular to the coronal planePXY.

FIG. 2 d shows the coordinate system X,Y,Z and planes PXY, PXZ of FIG. 2c, and the second, displaced, coordinate system X′, Y′, Z′ being thecoordinate system of the acetabulum 8, also shown in FIG. 2 b. The axisof the coordinate system of the acetabulum X′, Y′, Z′ having theirorigin O′ in the bottom of the acetabulum bowl 8, the axis X′ beingaligned with the caput and collum center axis. FIG. 2 d furtherdiscloses the vertical acetabulum plane PX′Y′ and the horizontalacetabulum plane PX′Z′, PX′Y′ being defined by the axis X′,Y′ and thevertical acetabulum plane PX′Z′ being defined by the axis X′,Z′. Theplanes PX′Y′ and PX′Z′ dividing the acetabulum bowl 8 into fourquadrants, the proximal-frontal quadrant 1807, the distal-frontalquadrant 1808, the distal-dorsal quadrant 1809 and the proximal-dorsalquadrant 1810, in accordance with what is previously disclosed, withreference to FIG. 2 b. FIG. 2 d further shows the location of foramenobturatum 1871.

FIG. 2 e shows, schematically how the acetabulum coordinate systemX′,Y′,Z′ relates to the hemisphere defined by the acetabulum bowl 8.

FIG. 2 f shows, schematically, how the vertical acetabulum plane PX′Y′,and the horizontal acetabulum plane PX′Z′ divides the acetabulum 8 intofour quadrants; the proximal-frontal quadrant 1807, the distal-frontalquadrant 1808, the distal-dorsal quadrant 1809 and the proximal-dorsalquadrant 1810, in accordance with the previously disclosed, withreference to FIGS. 2 b and 2 d.

FIG. 2 g shows the view of FIG. 2 d, and in addition it shows thehorizontal and vertical acetabulum planes PX′Y′ and PX′Z′ also being thecaput and collum femur horizontal and vertical planes PX′Y′ and PX′Z′,analogically dividing the caput and collum femur into four quadrants.

FIG. 3 a shows a perspective view of the hip joint in section,displaying the horizontal and vertical planes PX′Y′ and PX′Z′originating from the caput 5 and collum 6 center axis CX and dividingthe caput 5 and collum 6 femur into quadrants.

FIG. 3 b shows the proximal part of the caput femur 5 being removed e.g.by means of a bone saw. A surface of a section 102 is thus createdperpendicularly to a length axis of the collum femur 6

FIG. 4 a shows the reaming of the collum femur 6 and caput femur 5 usinga reamer 40 connecting to an elongated member 21 by a connecting section101. The reamer 40 creating a hemi-spherical cavity, having a concavesurface 103, centrally placed in the caput 5 and collum femur 6.

FIG. 4 b shows the step of applying an adhesive 106 to the createdhemi-spherical cavity in the femoral bone using an injecting member 104having an injecting nozzle 105. In the embodiment shown in FIG. 4 b theinjecting member is inserted into an area of the hip joint through ahole 18 in the pelvic bone 9, however it is equally conceivable that theinjecting member is inserted through the hip joint capsule 12 or thefemoral bone 7.

FIG. 5 shows the femoral bone 7 when a medical device 109 having aconcave contacting surface has been provided to the hemi-sphericalcavity, centrally placed in the caput 5 and collum femur. An elasticlayer 109 b adapted to absorb shocks from the femoral bone has beenplaced between the surface 109 c adapted to be in contact with theartificial caput femur surface, and the femoral bone 7, 6. The elasticlayer 109 b could be an elastic polymer layer, such as a polyurethane orsilicone layer. Having a layer absorbing shocks in the hip joint reducesthe risk of fastening elements in contact with bone being affected bystrains such that the fastening elements are loosened from theirrespective fastening positions, it also increases the comfort for thepatient.

FIG. 6 a shows the femoral bone 7 when a medical device having a concavecontacting surface 110 has been provided to the hemi-spherical cavity,centrally placed in the caput 5 and collum femur. The medical device hasbeen fixated to the femoral bone 7 using screws 121 placed aligned withthe caput and collum femur center axis and entering the cortical bone ofthe caput femur.

FIG. 6 b shows the femoral bone 7 when a medical device having a concavecontacting surface 110 has been provided to the hemi-spherical cavity,centrally placed in the caput 5 and collum femur. The medical devicecomprises fixating portions 680 extending on the outside of the surfaceof a section 102 of the surgically cut caput femur, comprising corticalbone in the periphery thereof, thereby stabilizing the medical devicewith the artificial concave acetabulum surface 110 in the surgically cutcaput femur.

FIG. 6 c shows an alternative embodiment, in which the medical devicehas been fixated to the surgically cut caput femur using screws 121entering the cortical bone 601 of the caput femur.

FIG. 6 d shows yet another embodiment, in which the medical device isfixated to the femoral bone using fixating portions, in accordance withthe embodiment described with reference to FIG. 6 b, and an elongatedmember 681. The elongated member is according to this embodiment athreaded member 681 extending along the collum and caput femur centeraxis, in the cancellous bone 602 of the collum femur, and entering thecortical bone 601 of the femoral bone, on the inside thereof, in thearea of the greater trochanter. The threaded elongated member 681creates an axial force when pulled pressing the medical device towardsthe surface of a section 102 of the surgically cut caput femur, therebystabilizing and fixating the medical device in the concave cavitycreated in the caput femur.

FIG. 6 e shows yet an alternative embodiment of the medical device inwhich the fixating portions 680 are additionally fixated using screws121 placed from the outside of the surgically cut caput femur,perpendicularly to the collum and caput femur center axis.

FIG. 7 a shows the medical device in an embodiment in which the fixatingportions 680 extends beyond the greatest circumference of the surgicallycut caput femur and thereby clasps the medical device to the surgicallycut caput femur, fixating the medical device thereon. The concavecontacting surface 110 is also adapted to travel beyond the equator ofan artificial caput femur which is placed in the artificial acetabulumwhen mounted into a functioning artificial hip joint, and clasping theartificial caput femur when mounted therein.

FIG. 7 b shows yet another embodiment where the medical device isadditionally fixated using a fixating band 683 encircling the fixatingportions of the medical device and thereby further clasping the medicaldevice to the surgically cut caput femur.

FIG. 7 c shows three different embodiment of medical devices comprisingfixating portions 680 which are slightly tilted towards the collum andcaput femur center axis, thereby clasping a portion of the surgicallycut caput femur for fixating the medical device to the surgically cutcaput femur. The three different embodiments shown is first, withoutscrews 121, second, with screws entering the cortical bone, and third,with screws penetrating the cortical bone and entering the medicaldevice on the inside of the concave cavity, which enables the screws tosqueeze a portion of the cortical bone for tight fixation of the medicaldevice.

FIG. 7 d shows two embodiments in which the concave contacting surface110 only comprises the part placed inside of the concave cavity. Thefirst embodiment shows the acetabulum surface 110 fixated to the concavecavity using screws 121, whereas the second embodiment shows theartificial acetabulum surface fixated without screws, such as using anadhesive.

FIG. 7 e shows two embodiments in which the artificial acetabulumsurface extends into a portion placed on the surface of a sectioncreated when the caput femur is surgically cut. In the first embodimentthe medical device is fixated using screws entering the cortical bone,whereas in the second embodiment the artificial contacting surface isfixated without screws, such as using an adhesive.

FIG. 7 f describes an embodiment in which the medical device is furtherfixated using an elongated member 681, fixating portions 680, and screws121 placed between the fixating portions 680 and the inside of theartificial acetabulum contacting surface 110. The elongated member 681is according to this embodiment a threaded member 681 and the first fig.discloses the preparation of the cancellous bone 602 with a curing fluid685, such as bone cement, creating a sturdy base for the fixation of thethreaded member 681.

FIG. 8 shows the artificial acetabulum surface 110 in further detailwhen the artificial acetabulum surface comprises a fixating portion 680extending on the outside of the cortical bone 601. The fixating portion680 is further fixated using screws 121 placed from the outside, througha hole in the medical device, penetrating the cortical bone 601 of thesurgically cut caput femur and entering the medical device placed in theconcave cavity in the caput femur.

FIG. 9 shows a section of the medical device according to the embodimentalso described with reference to FIG. 7 a, in further detail. Themedical device according to the embodiment in FIG. 9 comprises fixatingportions 680 which reaches on the outside of the surgically cut caputfemur and clasps the cortical bone of the caput femur. The medicaldevice clasps the caput femur since a distance 687, between the collumand caput femur center axis CA and the fixating portion in shorter thana distance 686 between the collum and caput femur center axis CA and aportion of the fixating portion placed more proximally when the medicaldevice is implanted. On the inside of the artificial concave acetabulumsurface, the surface extends beyond the equator of the artificial caputfemur adapted to be placed therein. An extending portion 682 clasps theartificial caput femur placed in the artificial acetabulum surface 110since a distance 688, between the collum and caput femur center axis CAand the inside of the artificial acetabulum surface 110 is shorter thana distance 689 between the collum and caput femur center axis CA and apoint on the inside of the artificial acetabulum contacting surface 110being more distal when the medical device is implanted.

FIG. 10 a shows the step of milling the periphery 690 of the corticalbone of the caput femur after the caput femur has been surgically cut,using a milling device 688 adapted therefor. The milling process createsa straighter edge which facilitates the fixation of a medical device onthe outside of the caput femur.

FIG. 10 b shows the milling of the inside of the cortical bone of thecaput femur after the caput femur has been surgically cut, using amilling device 689 adapted therefore, creating a straighter edge whichfacilitates the fixation of a medical device on the inside of the caputfemur.

FIG. 11 shows an artificial convex caput femur surface 112 adapted to beplaced in an artificial acetabulum surface according to any of theembodiments herein. After the artificial convex caput femur surface hasbeen placed in the artificial acetabulum surface it is locked using alocking member 116 comprising a surface 117 adapted to be in contactwith the artificial convex hip joint surface 112. The locking member 116further comprises fixating members 115 which are adapted to assist inthe fixation of the locking member 116 to the caput femur 5 or collumfemur 6, which in turns fixates the artificial convex hip joint surface112. The fixating members comprises a fixating portion 680 which travelson the outside of the surgically cut caput femur for radiallystabilizing and fixating the locking member to the surgically cut caputfemur. The artificial convex hip joint surface 112 is fixated to anelongated attachment rod 113 comprising a thread 114 and a recess 2203for enabling further movement of the prosthetic replacement for theacetabulum 110 in relation to the spherical portion 112 connected toelongated portion 2201.

FIG. 12 shows the artificial convex caput femur surface 112 as disclosedwith reference to FIG. 11 when mounted in an artificial acetabulumsurface 109 placed in a concave cavity in the femoral bone. Theartificial acetabulum surface is according to this embodiment is fixatedto the femoral bone using an elongated member 681, here being a threadedmember placed aligned with the collum and caput center axis.

FIG. 13 shows the artificial convex caput femur surface 112 as disclosedwith reference to FIG. 11 when mounted in an artificial acetabulumsurface 109 placed in a concave cavity in the femoral bone. Theartificial acetabulum surface is according to this embodiment is fixatedusing screws 121 entering the cortical bone of the surgically cut caputfemur.

FIG. 14 shows the injection of an adhesive 106 in the acetabulum 8 inthe pelvic bone 9 using an injecting member comprising an injectingnozzle 105, which is a preparation for the fixation of a medical deviceto the pelvic bone 9.

FIG. 15 shows the placing of a medical device in the reamed acetabulum 8surface of the pelvic bone 9. The medical device comprises a convex hipjoint surface 112 fixated to a fixation element 1301, which in turn isfixated to the acetabulum 8 using the injected fluid, which could beassisted or replaced by a mechanical fixation element such as screws.The medical device further comprises a pre-mounted locking member 116for locking the convex hip joint surface of the concave hip jointsurface placed in the caput 5 and collum femur 6 for hinderingdislocation of the hip joint when the hip joint is in its functionalposition. The artificial convex hip joint surface 112 is fixated to anelongated attachment rod 113 comprising a thread 114 and a recess 2203for enabling further movement of the prosthetic replacement for theacetabulum 110 in relation to the spherical portion 112 connected toelongated portion 2201.

FIG. 16 b shows the view of FIG. 16 a when a prosthetic acetabulumsurface 65 has been placed in the hemi-spherical cavity in the femoralbone replacing the natural contacting surface of the acetabulum 8. Theprosthetic replacement for the acetabulum 8 comprises two extendingportions 1823 a,b adapted to clasp the spherical portion 45 being aprosthetic part adapted to replace the natural collum femur 5 and thusfurther restraining the prosthetic spherical replacement for the caputfemur 45 in the prosthetic replacement for the acetabulum 65. Theprosthetic replacement for the acetabulum 65 and the prostheticspherical replacement for the caput femur 45 combined creating afunctional prosthetic hip joint. FIG. 16 b further shows an elongatedportion 2201, adapted to at least partially replace the collum femur.The prosthetic spherical portion 45 and the elongated portion 2201 areconnected to each other at the proximal portion of the elongated portion2201. According to the embodiment shown in FIG. 16 b the elongatedportion 2201 is adapted to be placed and fixated inside of bowl shapedacetabulum 8 as part of the pelvic bone 9. The elongated portion 2201restricts the movement of the prosthetic replacement for the acetabulum65 in relation to the spherical portion 45, especially since theprosthetic replacement for the acetabulum comprises extending portions1823 a,b extending beyond the equator line of the prosthetic replacementfor the acetabulum. The elongated portion thus further comprises arecess 2203 for enabling further movement of the prosthetic replacementfor the acetabulum 110 in relation to the spherical portion 112connected to elongated portion 2201.

FIG. 16 c shows a perspective view of the hip joint in section, similarto the embodiment shown in FIG. 16 b. However, in the embodiment of FIG.16 c the elongated portion 2201 comprises two recesses 2203 a,b, placedsuch that the elongated portion 2201 are adapted to receive theextending portions 1823 a,b through the extending portions 1823 a,bentering the recesses 2203 a,b of the elongated portion 2201 when theprosthetic replacement for the acetabulum 65 move in relation to theelongated 2201 and spherical 45 portions.

FIG. 16 d shows a perspective view of the hip joint in section, similarto the embodiment shown in FIGS. 16 b and 16 c. However, in theembodiment of FIG. 16 d the elongated portion 2201 is shaped such thatthe contacting portion between the elongated portion 2201 and thespherical portion 45 is eccentrically placed in relation to the centeraxis CX of the collum and caput femur. The eccentrically placedcontacting portion enables replacement for the acetabulum to move morein one direction than in another. This embodiment, similar to the recessembodiments previously disclosed, enables the adaptation of theelongated member to the prosthetic replacement for the acetabulum 65,and in particular the extending portions 1823 a,b thereof, for enablinga particular motion pattern of the hip joint and thus the leg.

FIG. 17 a shows a prosthetic spherical portion 45 and a prostheticelongated portion 2201 in a schematic view, displaying the prostheticelongated portion 2201 being connected to the prosthetic sphericalportion 45. According to the embodiment shown in FIG. 17 a the elongatedportion 2201 does not have any recesses or adaptations facilitating themovement of the prosthetic portions in relation to a prostheticreplacement for the acetabulum comprising extending portions.

FIG. 17 b shows a prosthetic spherical portion 45 and a prostheticelongated portion 2201 in a schematic view in an embodiment where theelongated portion comprises a recess 2203 a adapted to further enablemovement of the prosthetic replacement for the acetabulum 65 in relationto the prosthetic spherical 45 and elongated portions 2201.

FIG. 17 c shows a prosthetic spherical portion 45 and a prostheticelongated portion 2201 in a schematic view in an embodiment in which theelongated portion 2201 comprises two recesses 2203 a,b adapted tofurther enable movement of the prosthetic replacement for the acetabulum65 in relation to the prosthetic spherical 45 and elongated portions2201.

FIG. 17 d shows a prosthetic spherical portion 45 and a prostheticelongated portion 2201 in a schematic view in an embodiment in which theelongated portion 2201 is curved such that the area in which theelongated portion 2201 connects to the spherical portion 45 iseccentrically placed in relation to the collum and caput femur centeraxis CX.

FIG. 18 shows the prosthetic parts replacing the articulating surfacesof the hip joint. The prosthetic replacement for the acetabulum surface65 comprises extending portions 1823 a,b which are adapted to enter arecess 2203 of the prosthetic elongated portion 2201. The recess enablesfurther movement of the prosthetic replacement for the acetabulum 65 inrelation to the prosthetic spherical 45 and elongated portions 2201 inthe direction of recess, such as disclosed in the right part of FIG. 5,where the prosthetic part is placed in a state in which the prostheticreplacement for the acetabulum 65 is moved maximally in the direction ofthe recess 2203.

FIG. 19 a shows a cross-section of the prosthetic elongated portionwithout an adaptation to increase to motion range. This embodiment isdisclosed in a schematic side view in FIG. 17 a.

FIG. 19 b shows a cross-section of the prosthetic elongated portionhaving a recess 2203 or adaptation such that said prosthetic replacementfor the acetabulum 65 is adapted for further movement in relation to aprosthetic spherical 45 and elongated portion 2201 in the direction ofthe recess 2203 or adaptation. This embodiment is disclosed in aschematic side view in FIG. 17 b.

FIG. 19 c shows a cross-section of the prosthetic elongated portionwhere the restricting part of the elongated prosthetic portion is anarrow portion 2220, with a smaller cross-sectional area than otherportions of the elongated portion. In embodiments where the extendingportions of a prosthetic replacement for the acetabulum extendscircularly 360° around the collum and caput center axis, the circularnarrow portion 2220 disclosed in FIG. 19 c enables further movement ofthe prosthetic replacement for the acetabulum 65 in all radialdirections. This embodiment is disclosed in a schematic side view inFIG. 17 c.

FIG. 19 d shows a cross-section of the prosthetic elongated portioncomprising two recesses 2203 a and 2203 b or adaptations, into which aprosthetic replacement for the acetabulum can enter for furtherincreasing the motion range of the prosthetic hip joint in thedirections of the recesses or adaptations. This embodiment is disclosedin a schematic side view in FIG. 17 c.

FIG. 19 e shows a cross-section of the prosthetic elongated portionwherein the restricting portion of the elongated portion has a narrowsquare cross-section such that for increasing the motion range of theprosthetic hip joint more in the directions of the sides of the squarecross-section of the restricting portion of the elongated portion. Thisembodiment is disclosed in a schematic side view in FIG. 17 c.

FIG. 19 f shows a cross-section of the prosthetic elongated portionwherein the restricting portion of the elongated portion is more narrowthat other portions of the elongated portions and eccentrically placedin relation to the caput and collum center axis. The eccentric placementof the restricting portion of the elongated portion increases the motionrange of the prosthetic hip joint in the direction of the recess createdby the narrow portion being placed eccentrically. This embodiment isdisclosed in a schematic side view in FIG. 17 b.

FIG. 19 g shows a cross-section of the prosthetic elongated portionsimilar to the embodiment shown in FIG. 6 f. However in the embodimentshown in FIG. 19 g the narrow portion of the elongated portion is placedfurther eccentrically, further increasing the motion range of theprosthetic hip joint in the direction of the recess created by thenarrow portion being placed eccentrically.

FIG. 19 h shows a cross-section of the prosthetic elongated portion inwhich a portion of the elongated portion comprises a plurality ofrecesses 2203 which are adapted to a particular prosthetic replacementfor the acetabulum. According to the embodiment shown in FIG. 19 h therestricting portion is adapted for a prosthetic replacement for theacetabulum comprising extending portions with a circular surfaceentering the recess of the elongated prosthetic portion.

FIG. 19 i shows a cross-section of the prosthetic elongated portion,wherein said cross section is a more narrow elliptically shaped crosssection 2220 which enables further movement of the prostheticreplacement for the acetabulum 65 in the narrow direction of theelliptically shaped elongated portion.

FIG. 19 j shows a cross-section of the prosthetic elongated portion inwhich a portion of the elongated portion comprises two recesses 2203 a,bwhich are adapted to a particular prosthetic replacement for theacetabulum. According to the embodiment shown in FIG. 19 h therestricting portion is adapted for a prosthetic replacement for theacetabulum comprising extending portions with a circular surfaceentering the recess of the elongated prosthetic portion.

FIG. 19 k shows a cross-section of the prosthetic elongated portion inan embodiment similar to the embodiment sown in FIG. 19 j, however, inthe embodiment of FIG. 19 k the recesses 2203 a,b are somewhateccentrically placed in relation to the caput and collum center axis.The eccentrically placed recesses 2203 a,b thus altering the directionsin which the motion range are further increased, such that the recessescould be adapted to more critical motions that a patient is interestingin doing.

FIG. 20 a shows the prosthetic elongated portion 2201, also shown inFIG. 19 h, when placed in the prosthetic replacement for the acetabulum65 in a cross-sectional view, and in a side view. In the embodiment ofFIG. 20 a, the prosthetic replacement for the acetabulum surfacecomprises four extending portions 1823 a,b,c,d clasping the prostheticspherical portion 45 when implanted in the functional position in thehip joint. Each of the extending portions 1823 a,b,c,d of the prostheticreplacement for the acetabulum has a rounded shape adapted to matchcorresponding rounded recesses of the elongated portion 2201. By theextending portions 1823 a,b,c,d of the prosthetic acetabulum 65 enteringthe rounded recesses of the elongated portion 2201 the motion range ofthe prosthetic replacement for the acetabulum 65 is further increased.

FIG. 20 b shows the prosthetic elongated portion 2201, also shown inFIG. 6 i, when placed in the prosthetic replacement for the acetabulum65 in a cross-sectional view, and in a side view. In the embodiment ofFIG. 20 b, the prosthetic replacement for the acetabulum surfacecomprises two rounded extending portions 1823 c,d clasping theprosthetic spherical portion 45 when implanted in the functionalposition in the hip joint. The cross section of the prosthetic elongatedportion is a more narrow, elliptically shaped cross section whichenables further movement of the prosthetic replacement for theacetabulum 65 in the narrow direction of the elliptically shapedelongated portion, where according to this embodiment, the extendingportions of the prosthetic acetabulum is placed.

FIG. 20 c shows the prosthetic elongated portion 2201, also shown inFIG. 6 j, when placed in the prosthetic replacement for the acetabulum65 in a cross-sectional view, and in a side view. In the embodiment ofFIG. 20 c, the prosthetic replacement for the acetabulum surfacecomprises two rounded extending portions 1823 c,d clasping theprosthetic spherical portion 45 when implanted in the functionalposition in the hip joint. The two extending portions 1823 c,d of theprosthetic replacement for the acetabulum has a rounded shape adapted tomatch corresponding rounded recesses of the elongated portion 2201. Theshape of the prosthetic replacement for the acetabulum 65 is so adaptedthat the prosthetic replacement for the acetabulum can move along arelatively large motion range whilst the extending portions stillclasping the prosthetic spherical portion 45.

FIG. 20 d shows the prosthetic elongated portion 2201, also shown inFIG. 19 k, when placed in the prosthetic replacement for the acetabulum65 in a cross-sectional view, and in a side view. In the embodiment ofFIG. 20 d, the prosthetic replacement for the acetabulum surfacecomprises two rounded extending portions 1823 c,d, and onecircumferentially elongated extending portion 1823 b clasping theprosthetic spherical portion 45 when implanted in the functionalposition in the hip joint. The two extending portions 1823 c,d of theprosthetic replacement for the acetabulum has a rounded shape adapted tomatch corresponding rounded recesses of the elongated portion 2201. Thethird extending portion 1823 b is not extending as far as the two 1823 cand 1823 d, thus not limiting the motion range as much. The shape of theprosthetic replacement for the acetabulum 65 is so adapted that theprosthetic it can move along a relatively large motion range whilst theextending portions still clasping the prosthetic spherical portion 45.

FIG. 21 a shows pelvis in the same view as FIG. 2 b. Here the verticaland horizontal acetabulum planes PX′Y′ and PX′Z′ (further disclosed withreference to FIG. 2 d) are shown in a strict plane view. Two furtherplanes PX″Y″ is introduced in FIG. 3, which planes are rotated an angleα of 45° clockwise. The planes PX″Y″ and PX″Z″, in accordance with theplanes PX′Y′ and PX′Z′ divides the acetabulum bowl into four differentquadrants, being a proximal quadrant 1811, a frontal quadrant 1812, adistal quadrant 1813 and a dorsal quadrant 1814.

FIG. 21 b shows a perspective view of the hip joint in section,displaying the horizontal and vertical planes PX′Y′ and PX′Z′originating from the caput 5 and collum 6 center axis CX and dividingthe caput 5 and collum 6 femur into quadrants. FIG. 21 b further showsthe planes PX″Y″ and PX″Z″ dividing the acetabulum bowl into fourdifferent quadrants, being a proximal quadrant 1811, a frontal quadrant1812, a distal quadrant 1813 and a dorsal quadrant 1814, which isfurther disclosed with reference to FIG. 3 a.

FIG. 22 a shows a cross-section of an embodiment of the prostheticelongated portion 2201, wherein said elongated portion is eccentricallyplaced in relation to the collum and caput center axis CX. The eccentricplacement of the elongated portion 2201 places a large portion of theelongated portion 2201 a in the dorsal quadrant, smaller portions of theelongated portions 2201 b,d in the proximal and distal quadrants,respectively, and a smaller portion 2201 c is placed in the frontalquadrant. The placing of a larger portion of the restricting portion ofthe elongated portion 2201 in the dorsal quadrant 1814 limits the motionrange in the extension mostly. The movement range of the extensionmovements is less critical than for example flexion for every dayactivities, thus placing the major part of the elongated portion 2201 ain the dorsal quadrant restricts the motion range needed in a lesscritical way. The eccentrically placed elongated portion is furtherdisclosed with reference to FIGS. 19 f and 19 g.

FIG. 22 b shows a cross-section of an embodiment of the prostheticelongated portion 2201, wherein said elongated portion comprises arecess 2203, mainly placed in the frontal 1812, proximal 1811 and distal1813 quadrant, thus placing the major portion of the restricting portionof the elongated member in the dorsal quadrant 1814. The placing of alarger portion of the restricting portion of the elongated portion 2201in the dorsal quadrant 1814 limits the motion range in the extensionmostly. The movement range of the extension movements is less criticalthan for example flexion for every day activities, thus placing themajor part of the elongated portion 2201 a in the dorsal quadrantrestricts the motion range needed in a less critical way. The elongatedportion comprising a recess is further disclosed with reference to FIGS.17 b and 19 b.

FIG. 22 c shows a cross-section of an embodiment of the prostheticelongated portion 2201, wherein said elongated portion 2201 is curvedsuch that the connecting area between the prosthetic spherical portion45 and the prosthetic elongated portion 2201 is eccentrically placed inrelation to the caput and collum center axis CX, thus placing the majorportion of the restricting portion of the elongated member 2201 in thedorsal quadrant 1814. The placing of a larger portion of the restrictingportion of the elongated portion 2201 in the dorsal quadrant 1814 mainlylimits the motion range in extension of the leg. The movement range ofthe extension movements is less critical than for example flexion forevery day activities, thus placing the major part of the elongatedportion 2201 a in the dorsal quadrant restricts the motion range neededin a less critical way. The elongated portion comprising the curvedelongated portion is further disclosed with reference to FIG. 17 d.

FIG. 23 shows a medical device for implantation in a hip joint of apatient. The medical device is adapted to be fixated to the femoral boneof the patient, for example by means of an adhesive, such as bonecement, or mechanical fixating members, such as orthopedic screws. Themedical device comprises an inner 1827 and an outer 1828 surface. Acontacting portion of the inner surface 1827 is spherical and faces thecenter of the hip joint, when the medical device is implanted. Theinside of the medical device is adapted to receive a prostheticreplacement for a caput femur having a spherical portion, and thespherical contacting portion of the inner surface 1827 is adapted to bein contact with a spherical portion of the outer surface of theprosthetic replacement of the caput femur. The medical device, accordingto the embodiment shown in FIG. 17 comprises two extending portions 1823a,b, extending the contacting portion of the inner surface 1827′ suchthat the extending portions 1823 a,b clasps the spherical portion of aprosthetic replacement of a caput femur, for restraining the sphericalportion in the medical device. The medical device is adapted to receivethe prosthetic spherical portion, connected to the prosthetic elongatedportion. The inner surface 1827 comprises an equator line 1821, beingthe largest circular circumference of the inner surface. The twoextending portions passes beyond the equator line 1821, such that an endportion 1829 of the contacting portion, here being of the extendingportion 1823 b of the inner surface 1827, forms a circular extensionline 1822 placed proximal to the equator line 1821, when the medicaldevice is implanted, and having a smaller circumference than the equatorline 1821; thus a distance 1826 between a center axis P of the medicaldevice and the extension line 1822 is shorter than a distance 1825between the center axis P and the equator line 1821.

FIG. 24 shows the medical device described with reference to FIG. 23when implanted. According to this embodiment the medical device isadapted to be fixated using orthopedic screws 1830, mechanicallyfixating the medical device to the femoral bone 5, by the medical devicecomprising holes through which the screws 1830 are placed. In FIG. 5 thecontacting portion of the inner surface 1827 has been placed in contactwith the prosthetic spherical portion being connected to a theprosthetic elongated portion 2201, the prosthetic spherical 45 andelongated portions 2201 replacing the proximal portion of the femoralbone. The two extending portions 1823 a and 1823 b extending thecontacting portion of the inner surface and clasping the sphericalportion 45, for restraining the spherical portion in the medical device.The inner surface comprising the equator line 1821, and the extendingportions 1823 a,b passing beyond the equator line 1821 and comprisingthe more proximal extension line 1822 having a smaller circumferencethan the equator line 1821. The more proximal extension line 1822 beingplaced at a distance D1 from the equator line 1821. According to thisembodiment the extension line 1822 is parallel to the equator line 1821,however this is not necessarily so in other embodiments. The extensionportion 1823 a according to the embodiment shown in FIG. 11 extendscircumferentially along the equator line, a distance D2. Along anotherportion of the equator line, a distance D3, there are no extendingportion, which enables the elongated portion 2201 to enter the spacebetween the first and second extending portions 1823 a,b which creates alarger movement range of the hip joint, for further increase of themovement range, the recess 2203 in the elongated portion 2201 is adaptedfor some section of the extending portion to enter the recess 2203.

The extending portion, according to any of the embodiments, adapted toclasp the prosthetic spherical portion, for restraining it theprosthetic acetabulum 65, could further be adapted to release theprosthetic spherical portion 45 when a large enough strain is placed onthe joint. This feature enables the prosthetic spherical portion to befixedly attached in the prosthetic acetabulum 65 in normal use, and bereleased from the prosthetic acetabulum, e.g. in case of an accident,thus reducing the risk of damaging the bodily structures, such as thefemoral bone, or the fixations between bodily structures and prostheticparts.

According to one embodiment, the extending elements, are placed suchthat the extending elements restricts the motion range minimally, or inways which are not limiting the motion range used in everyday life. Thisis enabled through the placing of the extending portions, or theinteraction between the extending portion and adaptations of theprosthetic elongated portion. The hip joint is a synovial ball andsocket joint which permits a large motion range for allowing a pluralityof different movements of the lower limb. From a neutral position, thefollowing movements of the hip joint are normally possible: Lateral orexternal rotation, 30° with the hip extended, 50° with the hip flexed,medial or internal rotation 40°, extension or retroversion 20°, flexionor anteversion 140°, abduction 50° with hip extended, 80° with hipflexed, adduction 30° with hip extended, 20° with hip flexed. In themovement ranges of abduction and adduction the depth of the acetabulumbowl and thus the extending portions does not restrict the motion rangein a critical way since the motion range of the normal hip is restrictedin these movements, in normally agile persons, by the muscles, tenorsand ligaments surrounding the hip joint.

FIG. 25 a shows a frontal view of pubis and the proximal portions of thefemoral bones 7 when two embodiments prosthetic replacement for theacetabulum 65 has been implanted in the hip joint. The prostheticreplacements for the acetabulum shown comprises one extending portion1823, here placed dorsal to the vertical acetabulum plane PX′Y′ in thebase position, thus only partially limiting abduction in far excess of50°. According to the embodiment shown, the extending portion 1823extends circumferentially along the equator line 1821 about 1/10 of thelength of the equator line 1821, however in other embodiments theextending portion 1823 extends along as much as half of the length ofthe equator line 1821, and in other embodiments the extending portion1823 extends as little as about 1/30 of the length of the equator line1821. The prosthetic replacement for the acetabulum placed in the leftfemoral bone comprises two extending portions 1823 a,b, both beingplaced dorsal the corresponding vertical acetabulum plane PX′Y′ of theleft acetabulum (not shown) in the base position, thus limiting themotion range of the hip joint in a non restrictive way, in relation toeveryday activities. In both the right and left embodiment the extendingportions 1823 extends discontinuously along the equator line 1821 thusenabling the elongated portion 2201 to partially be placed between theequator line and the extension line, and in the left embodiment, beplaced between the extending portions 1823 a,b thus entering the cavitybetween the extending portions 1823 a,b. The recess 2203 of theprosthetic elongated portion 2201 implanted in the right hip joint isradially placed, in relation to the caput and collum center axis, suchthat the a section of the prosthetic elongated portion 2201, can enterthe recess for further increasing the movement range of the prostheticacetabulum surface 65 in relation to the elongated 2201 and spherical 45a portion. The curving of the prosthetic elongated portion 2201implanted in the left hip joint is radially placed, in relation to thecaput and collum center axis, for further increasing the movement rangeof the prosthetic acetabulum surface 65 in relation to the elongated2201 and spherical 45 b portion.

FIG. 25 b shows a frontal view of pubis and the proximal portions of thefemoral bones 7, when two further embodiments of the prostheticreplacements have been implanted. The embodiment shown placed on theright side is an embodiment in which the prosthetic elongated portion2201 a comprises a first 2203 a and second 2203 b recess placed at therestricting portion of the elongated portion 2201 a. The prostheticelongated portion is connected to a prosthetic spherical portion 45 awhich is restrained in a prosthetic replacement for the acetabulum 65 afixated to the femoral bone. The prosthetic replacement for theacetabulum 65 a comprises extending portions 1823 clasping theprosthetic spherical portion 45 a and thus restraining the sphericalportion in the prosthetic replacement for the acetabulum 65 a. Theextending portions 1823 is placed in the proximal quadrant in the baseposition, thus limiting the motion range of the hip joint in a nonrestrictive way, in relation to everyday activities. According to theembodiment shown, the extending portion 1823 extends circumferentiallyalong the equator line 1821 about 1/10 of the length of the equator line1821, however in other embodiments the extending portion 1823 extendsalong as much as half of the length of the equator line 1821, and inother embodiments the extending portion 1823 extends as little as about1/30 of the length of the equator line 1821. The prosthetic elongatedportion 2201 b shown placed in the left hip joint comprises a narrowportion connected to the prosthetic spherical portion 45 b. The narrowportion enables a relatively large motion range in relation to theelongated portion even though the prosthetic replacement for theacetabulum comprises extending portions 1823 a,b extending beyond theequator line of the prosthetic spherical portion 45 b, thus clasping thespherical portion and restraining it in a fixated position.

FIG. 26 shows the pelvis and the proximal portions of the femoral bones7 including the embodiment of FIG. 25 a, with the difference that thenatural caput femur and a portion of the natural collum femur has beenreplaced by a prosthetic replacement for the acetabulum. The prostheticelongated portion 2201 is here coordinated with the extending portions1823 of the prosthetic replacement for the acetabulum 65 a,b for furtherimproving the motion range of the hip joint, or not limiting the naturalmotion range of the hip joint.

FIG. 27 shows the medical device according to an embodiment in which themedical device comprises two extending portions 1823 a,b. The medicaldevice is placed on a prosthetic elongated portion 2201, to which aprosthetic spherical portion 45 is attached. The prosthetic elongatedmember 2201 is here adapted to further improve the motion range of thehip joint, or not limiting the natural motion range of the hip joint, bythe prosthetic elongated portion 2201 comprising a recess 2203 in whichthe extending portions 1823 can enter.

FIG. 28 a shows the pelvis in a lateral view, the prosthetic replacementfor the acetabulum 65 in the femoral bone comprises two extendingportions 1823 a,b, both extending circumferentially along the equatorline (as disclosed in for example FIG. 5) dorsal to the caudal-cranialaxis Y when being in the base position and being adapted to clasp thecaput femur or a prosthetic replacement therefor. The extending portions1823 a,b extending dorsal to the caudal-cranial axis Y when being in thebase position and thus reducing the limiting effect that the extendingportions 1823 a,b, have on the motion range of the hip joint. Accordingto the embodiment shown in FIG. 15 a the extending portion 1823 a,placed proximally in the acetabulum, extends circumferentially adistance of about ¼ of the length of the equator line, and the extendingportion 1823 b, placed distally in the acetabulum when being in the baseposition, extends circumferentially a distance of about 1/10 of thelength of the equator line, however it is equally conceivable that thisrelationship is the other way around, or that any of the extendingportions circumferentially extends a distance of as much as half of thelength of the equator line, thus extending the entire distance of theequator line being dorsal to the vertical acetabulum plane PX′Y′, orthat any of the extending portions 1823 a,b extends a distance being aslittle as 1/30 of the distance of the equator line. According to theembodiment shown in FIG. 15 a, the first extending portion 1823 aextends in distal-lateral direction from the acetabulum, and the secondextending portion 1823 b extends medially towards foramen obturatum whenbeing in the base position.

FIG. 28 b shows the pelvis in a lateral view, the prosthetic replacementfor the acetabulum 65 in the femoral bone comprises two extendingportions 1823 a,b, the two extending portions 1823 a,b extends in theproximal quadrant 1811 and the distal quadrant 1813 when being in thebase position, respectively.

There are multiple ways in which the extending portions 1823 can beadapted to reduce the effects that the extensions have on the motionrange of the hip joint.

FIG. 29 shows the pelvis in a lateral view, the prosthetic replacementfor the acetabulum 65 in the femoral bone shown comprises one extendingportion 1823 extending and being adapted to clasp the caput femur, or aprosthetic replacement therefor. The extending portion 1823 extendscircumferentially along the equator line within the proximal quadrant1811 when being in the base position, which is further disclosed withreference to FIG. 3. According to the embodiment shown in FIG. 10, theextending portion 1823 extends in distal-lateral direction from theacetabulum when being in the base position.

FIG. 30 shows the pelvis in a lateral view, the prosthetic replacementfor the acetabulum 65 in the femoral bone shown comprises a continuouslyextending portion 1823 with two extending portions 1823 a and 1823 bextending further in relation to the average extension of the extendingportion. The entire extending portion is placed in the proximal, distaland dorsal quadrants and the extending portions 1823 a,b extendingfurther than the average extension of the extending portion 1823 extendsin the proximal and distal quadrant when being in the base position.

FIG. 31 shows the pelvis in a lateral view, the prosthetic replacementfor the acetabulum 65 in the femoral bone shown comprises four extendingportions 1823 a,b,c,d, wherein the first 1823 a and second 1823 bextending portions extends in the proximal and distal quadrant,respectively, thus the first extending portion 1823 a extending indistal-lateral direction from the acetabulum, and the second extendingportion 1823 b extending medially towards foramen obturatum when beingin the base position. The third extending portion 1823 c when being inthe base position extending in the frontal quadrant 1812, out from theacetabulum in dorsal direction, extends less than the first and secondextending portion, since extending portions 1823 c in the frontalquadrant is more limiting to the normal motion range of the hip joint.The fourth extending portion 1823 d extends in the dorsal quadrant inaccordance with the third extending portion 1823 c do not extend as faras the first and second extending portions when being in the baseposition.

FIG. 32 shows an alternative embodiment of the prosthetic replacementfor the acetabulum 65. In the alternative embodiment, the prostheticreplacement for the acetabulum 65 comprises a first part 1841 adapted tobe fixated to the femoral bone of the patient. The first part comprisesan inner contacting surface adapted to be in movable connection with anouter contacting surface of a second part 1842. The second part 1842 isrotatably fixated to the first part 1841 by a rotatable connectingmember 1843. An outer contacting surface of a prosthetic sphericalportion 45 is adapted to be placed in contact with the inner surface ofthe second part 1842 and be movable in multiple directions, thusreplicating the natural ball and socket joint of the hip. The secondpart 1842 comprises two extending portions 1823 a,b extending beyond theequator line 1845 of the second part 1842. The extending portions 1823a,b extends longitudinally discontinuously along the equator line, thuscreating an area between the extending portions, in which area a portionof the prosthetic collum femur can be placed, thus being placedpartially between the equator line 1845 and the extension line 1846. Theconstruction shown in FIG. 26 enables the second part 1842 to rotate ifthe prosthetic elongated portion 2201 engages the extending portions1823 a,b, which are sloped for this purpose. This way the second part1842 are always placed such that the prosthetic elongated portion 2201can be placed partially between equator line 1845 and the extension line1846, which creates an optimal range of movement whilst the second partclasps the prosthetic spherical portion 45, and thus restricting thespherical portion 45 in the second part 1842 of the prostheticreplacement for the acetabulum 65.

FIG. 33 a shows the prosthetic replacement for the acetabulum 65according to one embodiment. In this embodiment the prostheticreplacement for the acetabulum 65 comprises two extending portions 1823a, b. The prosthetic replacement for the acetabulum 65 is according tothis embodiment adapted to be fixated to the femoral bone by means of anadhesive which is adapted to be placed in connection with the adhesiverecesses 1870 of the outer surface of the prosthetic replacement for theacetabulum 65.

FIG. 33 b shows a prosthetic replacement for the acetabulum 65 similarto the prosthetic replacement for the acetabulum 65 disclosed withreference to FIG. 33 a, but with the difference that it comprises threeequally extending portions 1823 a,b,c.

FIG. 33 c shows a prosthetic replacement for the acetabulum 65, similarto the prosthetic replacement for the acetabulum 65 disclosed withreference to FIG. 33 a, but with the difference that it comprises twoequally extending portions 1823 a,b and one less extending portion 1823c.

FIG. 33 d shows a prosthetic replacement for the acetabulum 65 similarto the prosthetic replacement for the acetabulum 65 disclosed withreference to FIG. 33 a, but with the difference that it comprises fourequally extending portions 1823 a,b,c,d.

FIG. 33 e shows a prosthetic replacement for the acetabulum 65 similarto the prosthetic replacement for the acetabulum 65 disclosed withreference to FIG. 33 a, but with the difference that the two extendingportions are placed further from each other, and thus being adapted tobe placed in the proximal and distal quadrant, when implanted and beingin the base position.

FIG. 33 f shows a prosthetic replacement for the acetabulum 65 similarto the prosthetic replacement for the acetabulum 65 disclosed withreference to FIG. 33 a, but further comprising a less extending portion1823 c placed between the first and second extending portions 1823 a,b.

The extending portions of the prosthetic replacement for the acetabulum65 which have been described could be made from an elastic material,enabling the extending portions to pass onto the a prosthetic sphericalportion, according to any of the embodiments herein.

FIG. 34 a shows the prosthetic elongated portion 2201, also shown inFIG. 7 a, when placed in the prosthetic replacement for the acetabulum65 in a cross-sectional view, and in a side view. In the embodiment ofFIG. 34 a, the prosthetic replacement for the acetabulum surfacecomprises four extending portions 1823 a,b,c,d clasping the prostheticspherical portion 45 when implanted in the functional position in thehip joint. Each of the extending portions 1823 a,b,c,d of the prostheticreplacement for the acetabulum has a rounded shape adapted to matchcorresponding rounded recesses of the elongated portion 2201. By theextending portions 2823 a,b,c,d of the prosthetic acetabulum 65 enteringthe rounded recesses of the elongated portion 2201 the motion range ofthe prosthetic acetabulum 65 is further increased. According to theembodiment shown in FIG. 34 a, the elongated portion 2201 is placedcentered in relation to the collum and caput center axis, such that thean equal portion of the elongated portion is placed in the proximal1811, distal 1813, frontal 1812 and dorsal 1814 quadrants, respectively.

FIG. 34 b shows the prosthetic elongated portion 2201, also shown inFIG. 20 b, when placed in the prosthetic replacement for the acetabulum65 in a cross-sectional view, and in a side view. In the embodiment ofFIG. 34 b, the prosthetic replacement for the acetabulum surfacecomprises two rounded extending portions 1823 c,d clasping theprosthetic spherical portion 45 when implanted in the functionalposition in the hip joint. The cross section of the prosthetic elongatedportion is a more narrow, elliptically shaped cross section whichenables further movement of the prosthetic replacement for theacetabulum 65 in the narrow direction of the elliptically shapedelongated portion, where according to this embodiment, the extendingportions of the prosthetic acetabulum is placed. The prostheticreplacement for the acetabulum 65 and the prosthetic elongated portion2201 are oriented in relation to the acetabulum, such that the extendingportions 1823 c,d are placed in the proximal 1811 and distal 1813quadrant when being in the base position, and the major parts of theelongated portion 2201 are placed in the frontal 1812 and dorsal 1814quadrants, while only minor parts are placed in the proximal 1811 anddistal 1813 quadrants. This configuration enables the prostheticreplacement for the acetabulum 65 to have extending portions 1823 c,d,and the elongated portion to have a relatively large cross-sectionwithout restricting the motion range of the hip joint in excess of therestriction of a natural hip joint, in any direction.

FIG. 34 c shows the prosthetic elongated portion 2201, also shown inFIG. 20 c, when placed in the prosthetic replacement for the acetabulum65 in a cross-sectional view, and in a side view. In the embodiment ofFIG. 21 c, the prosthetic replacement for the acetabulum surfacecomprises two rounded extending portions 1823 c,d clasping theprosthetic spherical portion 45 when implanted in the functionalposition in the hip joint. The two extending portions 1823 c,d of theprosthetic replacement for the acetabulum 65 has a rounded shape adaptedto match corresponding rounded recesses of the elongated portion 2201.The shape of the prosthetic replacement for the acetabulum 65 is soadapted that the prosthetic replacement for the acetabulum 65 can movealong a relatively large motion range whilst the extending portionsstill clasping the prosthetic spherical portion 45. This configurationenables the prosthetic replacement for the acetabulum 65 to haveextending portions 1823 c,d, and the elongated portion to have arelatively large cross-section without restricting the motion range ofthe hip joint in excess of the restriction of a natural hip joint, inany direction.

FIG. 34 d shows the prosthetic elongated portion 2201, also shown inFIG. 20 d, when placed in the prosthetic replacement for the acetabulum65 in a cross-sectional view, and in a side view. In the embodiment ofFIG. 34 d, the prosthetic replacement for the acetabulum 65 comprisestwo rounded extending portions 1823 c,d, and one circumferentiallyelongated extending portion 1823 b clasping the prosthetic sphericalportion 45 when implanted in the functional position in the hip joint.The two extending portions 1823 c,d of the prosthetic replacement forthe acetabulum 65 has a rounded shape adapted to match correspondingrounded recesses of the elongated portion 2201. The third extendingportion 1823 b is not extending as far as the two 1823 c and 1823 d,thus not limiting the motion range as much. The shape of the prostheticreplacement for the acetabulum 65 is so adapted that the prostheticreplacement for the acetabulum 65 can move along a relatively largemotion range whilst the extending portions still clasping the prostheticspherical portion 45. The prosthetic replacement for the acetabulum 65and the prosthetic elongated portion 2201 are oriented in relation tothe acetabulum, such that the extending portions 1823 c,d are placed inthe proximal 1811 and distal 1813 quadrant when being in the baseposition, where only minor parts of the elongated portion 2201 areplaced. A large portion if the elongated portion 2201 is placed in thedorsal quadrant 1814, where no extending portion is present, while asmaller, but still relatively large portion of the elongated portion2201 is placed in the frontal 1812 quadrants, where a less extendingportion is placed. This configuration enables the prosthetic replacementfor the acetabulum 65 to have extending portions 1823 c,b,d in threedirections, creating a very stable configuration, whilst still enablingthe elongated portion to have a relatively large cross-section withoutrestricting the motion range of the hip joint in far excess of therestriction of a natural hip joint.

Examples of embodiments of different adaptations of the elongatedportion, alone, or adaptations in conjunction with correspondingadaptations of the prosthetic replacement for the acetabulum have beenshown. The placement of the elongated member in relation to theprosthetic replacement for the acetabulum is critical to the obtainedmotion range for a prosthetic hip joint comprising a prostheticreplacement for the acetabulum with portions extending beyond theequator of the spherical portion clasped therein. According to someembodiments 1/10 of the cross section of the restricting portion of theelongated member is placed in the proximal and distal quadrants, whereas9/10 are placed in the frontal and dorsal quadrants, which 9/10 could beequally distributed between the two quadrants, or a major part, such as6/10 could be placed in the dorsal quadrant and 4/10 could be placed inthe frontal quadrants, however it is equally conceivable that it is theother way around depending of the design of the prosthetic replacementfor the acetabulum. In embodiments comprising deep recesses oradaptations, or in embodiments where the restricting portion of theelongated portion is placed eccentrically in relation to the collum andcaput center axis, as little as 0/10 of the elongated portion could beplaced in a particular quadrant and from that the entire range from1/10- 10/10 of the restricting portion of the elongated portion could beplaced in any of the quadrants to obtain an advantageous motion range,all depending on the placement of the prosthetic replacement for theacetabulum in relation to the femoral bone, and in particular theextending portions of the prosthetic replacement for the acetabulum whenbeing in the base position.

The medical device according to any of the embodiments could comprise atleast one material selected from a group consisting of:polytetrafluoroethylene (PTFE), perfluoroalkoxy (PFA) and fluorinatedethylene propylene (FEP). It is furthermore conceivable that thematerial comprises a metal alloy, such as cobalt-chromium-molybdenum ortitanium or stainless steel, or polyethylene, such as cross-linkedpolyethylene or gas sterilized polyethylene. The use of ceramic materialis also conceivable, in the contacting surfaces or the entire medicaldevice such as zirconium or zirconium dioxide ceramics or aluminaceramics. The part of the medical device in contact with human bone forfixation of the medical device to human bone could comprise a poorhousestructure which could be a porous micro or nano-structure adapted topromote the growth-in of human bone in the medical device for fixatingthe medical device. The porous structure could be achieved by applying ahydroxy-apatite (HA) coating, or a rough open-pored titanium coating,which could be produced by air plasma spraying, a combination comprisinga rough open-pored titanium coating and a HA top layer is alsoconceivable. The contacting parts could be made of a self lubricatedmaterial such as a waxy polymer, such as PTFE, PFA, FEP, PE and UHMWPE,or a powder metallurgy material which could be infused with a lubricant,which preferably is a biocompatible lubricant such as a Hyaluronic acidderivate. It is also conceivable that the material of contacting partsor surfaces of the medical device herein is adapted to be constantly orintermittently lubricated. According to some embodiments the parts orportions of the medical device could comprise a combination of metalmaterials and/or carbon fibers and/or boron, a combination of metal andplastic materials, a combination of metal and carbon based material, acombination of carbon and plastic based material, a combination offlexible and stiff materials, a combination of elastic and less elasticmaterials, Corian or acrylic polymers.

Please note that any embodiment or part of embodiment as well as anymethod or part of method could be combined in any way. All examplesherein should be seen as part of the general description and thereforepossible to combine in any way in general terms.

According to the above mentioned embodiments the medical device isadapted to be inserted through a hole in the pelvic bone, however it isequally conceivable that the medical device according to any of theembodiment above is adapted to be inserted through a hole in the hipjoint capsule or the femoral bone of the human patient.

Please note that any embodiment or part of embodiment as well as anymethod or part of method could be combined in any way. All examplesherein should be seen as part of the general description and thereforepossible to combine in any way in general terms.

1. A medical device for implantation in a hip joint of a patient, thenatural hip joint having a ball shaped caput femur integrated with acollum femur having a collum and caput center axis, extendinglongitudinal along the collum and caput femur, in the center thereof, asthe proximal part of the femoral bone with a convex hip joint surfacetowards the centre of the hip joint and a bowl shaped acetabulum as partof the pelvic bone with a concave hip joint surface towards the centreof the hip joint, the medical device comprising; an artificial caputfemur comprising a convex surface towards the centre of the hip joint,an elongated portion adapted to be connected to a prosthetic sphericalportion of said artificial convex caput femur and fixated to the pelvicbone of the human patient, wherein said artificial convex caput femur isadapted to, when implanted: a. be fixated to the pelvic bone of thehuman patient through said elongated portion fixation to the pelvicbone, and b. be in movable connection with a prosthetic artificialacetabulum surface fixated to the femoral bone of the patient,comprising at least one extending portion adapted to clasp saidprosthetic spherical portion, wherein c. said elongated portioncomprises a restricting portion adapted to restrict the motion range ofthe artificial acetabulum in relation to said artificial convex caputfemur, and wherein d. said restricting portion of said elongated portionis adapted to enable an advantageous motion range in relation to saidartificial acetabulum.
 2. The medical device according to claim 1,wherein said elongated portion comprises at least one recess adapted toreceive a portion of said prosthetic artificial acetabulum, whenimplanted.
 3. The medical device according to claim 2, wherein saidrecess is adapted to be placed frontal to the coronal pelvis plane, whenimplanted.
 4. The medical device according to claim 2, wherein saidrecess is adapted to be placed in the frontal quadrant, when implanted.5. The medical device according to claim 2, wherein said recess isadapted to be placed in the dorsal quadrant, when implanted.
 6. Themedical device according to claim 2, wherein said recess is adapted tobe placed in the proximal quadrant, when implanted.
 7. The medicaldevice according to claim 2, wherein said recess is adapted to be placedin the distal quadrant, when implanted.
 8. The medical device accordingto claim 2, wherein said recess is more than 2 mm deep.
 9. The medicaldevice according to claim 2, wherein said recess is more than 4 mm deep.10. The medical device according to claim 2, wherein said recess is morethan 6 mm deep.
 11. The medical device according to claim 2, whereinsaid recess is more than 8 mm deep.
 12. The medical device according toclaim 1, wherein said elongated portion comprises an adaptation adaptedto receive said extending portion when implanted.
 13. The medical deviceaccording to claim 12, wherein said adaptation comprises a bent portionof said elongated portion.
 14. The medical device according to claim 13,wherein said bent portion is bent such that said restricting portion ofsaid elongated portion mainly is placed frontal to the coronal pelvisplane, when implanted.
 15. The medical device according to claim 13,wherein said bent portion is bent such that said restricting portion ofsaid elongated portion mainly is placed dorsal to the coronal pelvisplane, when implanted.
 16. The medical device according to claim 13,wherein said bent portion is bent such that said restricting portion ofsaid elongated portion mainly is placed in the frontal quadrant, whenimplanted.
 17. The medical device according to claim 13, wherein saidbent portion is bent such that said restricting portion of saidelongated portion mainly is placed in the dorsal quadrant, whenimplanted.
 18. The medical device according to claim 13, wherein saidbent portion is bent such that said restricting portion of saidelongated portion mainly is placed in the proximal quadrant, whenimplanted.
 19. The medical device according to claim 13, wherein saidbent portion is bent such that said restricting portion of saidelongated portion mainly is placed in the distal quadrant, whenimplanted.
 20. The medical device according to claim 1, wherein across-section of said restricting portion of said elongated portion,perpendicular to the caput and collum center axis, comprises a firstdistance and a second distance, wherein a center point of a line of saidfirst distance intersects a center point of a line of said seconddistance, and wherein said first distance is shorter than said seconddistance. 21.-70. (canceled)